synlpc2.txt

简单lpc音码器与声激励lpc音码器比较

function synWave=synlpc2(aCoeff,source,sr,G,fr,fs,preemp)
if(nargin<5),fr=20;end;
if(nargin<6),fs=30;end;
if(nargin<7),preemp=.9378;end;
msfs=round(sr*fs/1000);
msfr=round(sr*fr/1000);
msoverlap=msfs-msfr;
ramp=[0:1/(msoverlap-1):1]';
[L1 nframe]=size(aCoeff);
[row col]=size(source);
if(row==1|col==1)
    postFilter=0;duration=length(source);frameIndex=1;
    for sampleIndex=1:msfr:duration-msfs+1;
        resid(:,frameIndex)=source(sampleIndex:(sampleIndex+msfs-1))';
        frameIndex=frameIndex+1;
    end
else
    postFilter=1;resid=source;
end
[row col]=size(resid);
if col<nframe
    nframe=col;
end
for frameIndex=1:nframe
    A=aCoeff(:,frameIndex);
    residFrame=resid(:,frameIndex)*G(frameIndex);
    synFrame=filter(1,A',residFrame);
    if(frameIndex==1)
        synWave=synFrame(1:msfr);
    else
        synWave=[synWave;overlap+synFrame(1:msoverlap).*ramp:...
                synFrame(msoverlap+1:msfr)];
    end
    if(frameIndex==nframe)
        synWave=[synWave;synFrame(msfr+1:msfs)];
    else
        overlap=synFrame(msfr+1:msfs).*flipud(ramp);
    end
end;
if(postFilter)
    synWave=filter(1,[1-preemp],synWave);
end